I have just noticed that xampp and its links in the admin page are working properly from remote computer (PC2). When I write either http://PC1/ or http://10.0.0.2/ in the browsers address line, xampp welcome page opens and all links in the page are working properly.

It is still not working for my websites located under /xampp/htdocs directory.

On PC1 (sitting in front of it) you type in the browser http://localhost and the XAMPP is coming up.
in the xampp you have installed your pages in \xampp\htdocs\mypage
also you type http://localhost/mypage and you smile for happyness

It looks like a relative address problem, but this is a professional script for installing on web servers and if it uses an absolute address instead of relative address, no one can reach the webpages. So it shoul be something else. The script and all other files are written in php code.

There is also one DNS server in system (it is a DSL router modem - Speedtouch 510) and it gives uniqe static IP number to the each PC.